Oven door window unit



Feb. 2, 1965 Filed Sept. 24, 1963 R. B. LARKIN 3,168,089

OVEN DOOR WINDOW UNIT 2 Sheets-Sheet 1 MMMM Feb. 2, 1965 R. B. LARKIN 3,168,089

OVEN DOOR WINDOW UNIT Filed Sept. 24, 1965 2 Sheets-Sheet 2 INVENTOR. 702672 fi AarXz'zz United States Patent 01 3,168,089 OVEN DUOR WINDOW UNKT Robert B. Larkin, Farmington, Mich, assignor to Mills Products, Inc., Walled Lake, Mich, a corporation of Michigan Filed Sept. 24, 1363, Ser. No. 311,081 6 Claims. (Cl. 126-200) This invention relates to oven door windows and has particular reference to a double glazed window unit which is constructed so as to eliminate condensation on the inner surfaces of the glass panels. A unit embodying the invention is particularly designed for use in domestic and commercial bake ovens but it is also useful for all types of oven closures.

In domestic and commercial ovens where baking and roasting operations are performed, the oven atmosphere is heavily laden with moisture, and it is desirable to prevent such moisture from condensing on the inner surfaces of the glass panels. This problem of moisture condensation on the inner surfaces of the glass panels has become acute in stoves having sealed ovens. In such sealed ovens the moisture, instead of escaping around the periphery of the door as was possible in the past, is driven into the space between the closure panels and tends to collect on the inner surfaces of the window panels which in time causes the window to fog and thus impairs the utility of the window.

A principal object of the invention here is to provide a novel and inexpensive construction for a double glazed window unit whereby the space between the glass panels is sealed so as to exclude such moisture laden atmosphere from the oven. Additionally, the construction provides for the circulation of room air through the space between the glass panels so as to prevent condensation of moisture on such surfaces when the closure cools down after the oven has been used.

Other and further objects of the invention will be apparent from the following description and claims and may be understood by reference to the accompanying drawings, of which there are two sheets, which by way of illustration show preferred embodiments of the invention and what I now consider to be the best mode of applying the principles thereof. Other embodiments of the invention may be used without departing from the scope of the present invention as set forth in the appended claims.

In the drawings:

FIG. 1 is an elevational view of a window unit em bodying the invention;

FIG. 2 is a fragmentary sectional view taken along line 22 of FIG. 1;

FIG. 3 is an enlarged sectional view taken along the line 3-3 of FIG. 1;

FIG. 4 is a view similar to FIG. 3 but illustrating a modified form of the invention;

FIG. 5 is a fragmentary view similar to FIG. 1 but illustrating a further modified form of the invention; and

FIG. 6 is an enlarged sectional view taken along the line 66 of FIG. 5.

As illustrated in FIGS. 1, 2 and 3, a making oven 10 is provided with a closure 12 which includes a double glazed window unit 14. The inner and outer Walls or panels 16 and 18 of the closure are each provided with an opening defined by inturned flanges 20 and 22, and the window unit is disposed within such openings, the flanges 20 and 22 cooperating with beads 24 and 26 of the window unit for locating the window unit in the door opening.

The window unit includes a pair of tempered glass panels 28 and 30, a metal spacer 32 disposed between the panels at the edges thereof, a strip of sealing tape, preferably adhesive-backed aluminum foil 34, which is "ice wrapped around the peripheral edges of the panels 28 and 3t] and overlaps the outer sides thereof, and a rigid mounting frame 36 which extends around the periphery of the taped panels.

The construction of the window unit is similar to that illustrated in Mills Patent No. 3,021,832, issued February 20, 1962, for Stove Door Window Unit, in that the glass panels 28 and 30, the spacer 32, and the clamping frame 36 preferably are of the same construction as the corresponding elements as illustrated in the Mills patent. There are, however, a number of important and significant differences between the construction of the present invention and the construction disclosed in the Mills patent in that according to the present invention the adhesive-backed tape 34 is wrapped around the peripheral edges of the glass panels 28 and 30 and adhesively secured thereto so as to secure the panels together with the spacer 32 therebetween so as to form a unit. The adhesive 35 preferably is a silicone pressure-sensitive adhesive capable of withstanding temperatures of 550 F. without deterioration. As the tape is impervious to mois tnre, the tape wrapped around the peripheral edges of the glass panels and adhesively secured thereto serves to provide an effective moisture-tight seal for the space between the panels 28 and 30. In addition, the tape serves to bind the glass panels 28 and 3t) together so as toform a unit and to hold the same in proper relation with respect to each other while the clamping frame 36 is applied thereto.

The clamping frame 36 preferably comprises a continuous strip of sheet metal which forms a wrap-around clamping frame of channel-shaped cross section and wherein the ends of the frame are interconnected by a tongue and slot connection as shown in the Mills Patent No. 3,021,832. Thus, after the clamping frame 36 is applied to the tape-wrapped glass panels, the tape is disposed between the edges of the glass panels and the bottom of the channel of the clamping frame, as shown in FIG. 3, and the sides 40 and 42 of the clamping frame reacting on the tape 34 serve to hold the glass panels 28 and 3t) tightly against the parallel sides of the spacer 32.

The sides 4% and 42 of the clamping frame 36 preferably are formed with beads 24- and 26 which cooperate with the inturned flanges 20 and 22 on the door panels: so as to locate the window unit with respect tothe opening in the closure 12. A coating 35 of adhesive on one side of the tape will usually suffice whereby the tape may be readily wrapped around and applied to the periphery of the glass panels 2-8 and 35 before such panels are assembled in the frame 36. With this arrangement the tape 34 provides an effective moisture-proof seal for the space between the panels 28 and 30. However, rather than evacuating air from the sealed space between the panels 23 and 34), 1 form one or more breather holes 44 in the outer glass panel 30. These holes can be of about one-eighth to one-sixteenth of an inch in diameter and provide for the circulation of room air into the space between the panels 28 and 3t). As the temperature of the oven rises, the temperature of the air between the panels also rises, and this causes such air to expand and how out through the holes 44, thus preventing a build-up in pressure between the panels. Since the temperature between the panels 28 and .30 is higher than the room temperature, and since the tape 34 prevents moisture from the oven from entering the space between the panels 28 and 30, no condensation will form on the inner surfaces of the panels 28 and 30 when the oven is operating. After the oven is turned off and cools down, the air between the panels 28 and 30 will contract and room air will flow into such space through the openings 44. Since the moisture content of the air which flows from the room into the space between the panels 28 and 30 will be that of the room air, and since the temperature of the glass panels 28 and 30 will not fall below room temperature, no condensation will form on the inner surfaces of the panels 23 and 30.

Instead of wrapping the periphery of the glass panels 28 and 30 with a single tape 34 as shown in FIGS. 1, 2 and 3, two tapes Stl and 52 may be employed as shown in FIG. 4, the tapes 50 and 52 being the same as the tape 34. Thus it will be sutlicient that each of the tapes 50 and 52 overlap the outer side of one of the panels 28 and 30 and one of the legs 54 of the spacer 32. Since the spacer 32 is metal and impervious, the arrangement as illustrated in FIG. 4 will effectively seal the space between the panels 28 and 30 against the entrance of oven moisture, as does the arrangement of FIGS. 1 to 3.

I have found to be satisfactory for use in practicing the invention an aluminum foil tape coated with pressuresensitive silicone adhesive Where the foil has a nominal thickness of .002 inch and where the adhesive is capable of withstanding temperatures of 550 F. However, other tapes and adhesives capable of withstanding such temperatures may also be used. It is also important that the tape and adhesive be capable of withstanding the low ambient temperatures which may be encountered in shipping and storing stoves. The silicone adhesive aluminum foil tape above referred to provides a flexible seal which permits expansion and contraction of the glass without straining as the temperature of the window varies.

in the construction illustrated in FIGS. and 6, instead of using the breather holes 44 in the glass panel 30 exposed to the room, the spacer and the frame may be made so as to permit breathing between the edge of the glass and the adjacent edge of the frame. Thus in FIGS. 5 and 6 the spacer 134 along one edge is provided with one or more dimples or projections 136, and the adjacent lower edge of the frame is likewise provided with one or more dimples or projections 138 whereby the lower edge of the glass panel is slightly spaced from the leg 152 of the spacer and from the lower portion 154 of the frame. This serves to space the glass panel from the spacer and the frame between the projections 136 and 138 so as to provide a breather passage or opening between the space enclosed by the panels 28 and 30 and the spacer 134 and the area to which the glass: panel 30 is exposed.

In this modification the frame 140 for the unit is provided with an L-shaped lower wall 154 and a part 142 which carries a trim band 144 which overlaps the joint between the glass panel 30 and the outer panel or wall 160 of the oven closure. strip 52 of FIG. 4 is secured by adhesive 14 to the leg 152 of the spacer 134 and to the inner surface of the frame 149 so that the tape is spaced from the lower edge of the glass panel 39 except at the projections 136 and A strip of tape 162 like the 138 so as to provide the communication with the space between the glass panels 28 and 30 above referred to. It will be sufiicient to provide the breather along one edge of the glass panel 30, such as the lower edge, Whereby the side and top edges of the glass panel 30 may be sealed to the spacer 134 as illustrated with respect to the glass panel 28 by a separate strip, such as 50. However,

the breather may be provided in the manner shown in FIG. 6 along two or even all four edges of the glass panel and in the latter case the trim band or bezel 144 may contact the outer surface of the glass panel 30 to clamp it against the spacer.

While I have illustrated and described preferred embodiments of my invention, it is understood that these are capable of modification, and I therefore do not wish to be limited to the precise'details set forth but desire to avail myself of such changes and alterations as fall within the purview of thefollowing claims.

I claim:

1. A window unit for an oven door comprising a pair of spaced tempered glass panels, a metal spacer disposed between said panels at the edges thereof, the peripheral edges of said panels being bound with sealing tape whereby said panels are secured together as a unit with said spacer therebetween, a rigid mounting frame extending around the periphery of said taped panels and in which said unit is clamped, said tape comprising a metal foil, a silicone adhesive sealing said tape to the peripheral edges of said panels, said unit being provided with a breather opening from one side thereof into the space between said glass panels. 7

2. A window unit according to claim 1 wherein said breather opening comprises a hole in one of said glass panels.

3. A window unit according to claim 1 wherein said breather opening is formed between the peripheral portion of one of said glass panels and said frame.

4. A window unit according to claim 1 wherein said tape comprises aluminum foil.

5. A window unit according to claim 1 wherein said breather opening is provided by means which space an edge portion of one of said glass panels from adjacent portions of said frame and spacer.

' 6.A window unit according to claim 1 wherein said sealing tape comprises strips of tape, one secured to the peripheral edge of each of said panels and adjacent portions of said spacer.

References Cited in the file of this patent UNITED STATES PATENTS 2,419,400 Haven Apr. 22, 1947 2,974,377 -Kunkle Mar. 14, 1961 

1. A WINDOW UNIT FOR AN OVEN DOOR COMPRISING A PAIR OF SPACED TEMPERED GLASS PANELS, A METAL SPACER DISPOSED BETWEEN SAID PANELS AT THE EDGES THEREOF, THE PERIPHERAL EDGES OF SAID PANELS BEING BOUND WITH SEALING TAPE WHEREBY SAID PANELS ARE SECURED TOGETHER AS A UNIT WITH SAID SPACER THEREBETWEEN, A RIGID MOUNTING FRAME EXTENDING AROUND THE PERIPHERY OF SAID TAPED PANELS AND IN WHICH SAID UNIT IS CLAMPED, SAID TAPE COMPRISING A METAL FOIL, A SILICONE ADHESIVE SEALING SAID TAPE TO THE PERIPHERAL EDGES OF SAID PANELS, SAID UNIT BEING PROVIDED WITH A BREATHER OPENING FROM ONE SIDE THEREOF INTO THE SPACE BETWEEN SAID GLASS PANELS. 